[Heathkit] Heathkit SB Essay.

[Van K7VS]

My goodness!  With that report I am really surprised they sold more then ten 
of anything!  Geez, I am going to start selling off my Heathkit collection 
(including an unbuilt SB220!)   Van, K7VS Medford,


----- Original Message ----- 
From: <kiyoinc at attglobal.net>
To: <heathkit at mailman.qth.net>
Sent: Wednesday, July 11, 2007 6:21 PM
Subject: [Heathkit] Heathkit SB Essay.


>I wrote this the other day, here is a fresh edit:
>
> On Heathkit SB's.
>
> The problem with Heathkit's SB transceivers isn't the soldering.
> That's an old-ham's saw.  It's not quite up there with the "Acid Core"
> urban legend, but it's close.
>
> While I have encountered poor solder jobs, I have only seen one
> problem that was clearly solder based and that was in a factory,
> machine-made part.
>
> The problem with Heath are the mechanicals.  The design is clever;
> the parts are mediocre; the mechanical build quality is generally
> horrible.
>
> A case in point is the LMO pinch drive and the tension on the rings.
> I've spent hours cleaning, polishing, and adjusting the drive and when 
> it's right, it's terrific.  It's light, smooth, precise, no backlash. I 
> have a Heath SB tuning knob with lead weights in it.  It's a perfect match 
> for the LMO drive.
>
> I had an SB pinchdrive shaft that was dragging. 35 years of corrosion will 
> do that to metal. I hand polished the shaft with 1200 grit, oiled it, got 
> it turning right in the brass sleeve.
>
> I carefully cleaned the LMO dial ring and tensioned the drive disks. Then 
> it takes several times of trial and error to get the disks on the right 
> part of the ring.
>
> Even when you have the pinch drive adjusted right, the 100 kHz
> indicator is off.  That's a 30 minute trial and error adjustment where
> 1/64 inch position shift of a piece of metal under a machine screw is
> amplified by an articulated arm.    After the fine tuning, you're
> fighting the play in stamped parts.
>
> Then there's the fiduciary on the LMO.  What's with that?
>
> Every fiduciary knob is corroded.  I polished one until it shines.
> It's still just a knob on a 1/8 inch shaft in a hole drilled in plastic, 
> no fore-aft stop, driving a piece of wobbly plastic with friction.  The 
> plastic hairline may have chips on the edge.  Nothing you can do about 
> that.
>
> Another problem with Heath are the thin skirts on the knobs.  The
> skirts could be thicker and more precise.  When I put the knobs back
> on a Heath, I use a feeler gauge to space the skirt from the front
> panel. 1/8th inch is about right. That's after I find the low spot on the 
> skirt.
>
> This is after I clean the dirt out of the knob flutes with a wood 
> toothpick and polish the plastic with a silk cloth.
>
> The bezel on the SB's should be more like Collins.  That was a bad
> place for Heath to cut corners. A thick solid bezel would give the
> fiduciary's drive shaft more bearing surface.
>
> How did Heath get the bezels on the DX-60 and the HW-16 so right and
> the SB so wrong?
>
> The phenolic circuit boards are mediocre.  The design is fine.  Thick
> FR4 glass epoxy would have made the Heath's much better.
>
> On sheer performance, the Heath's are up there. The 6HS6 (or FETs in the 
> SB-303)) give .25 microvolt sensitivity. Hot receivers, 6 pole
> crystal filters, rock-stable, 1 kHz readout, etc. Transceiver slaved to a 
> full Receiver. Drake and Halli couldn't do that well until they went 
> digital.
>
> de ah6gi/4
>
>
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